class_docstr: [summary]
  
  Args:
    test {[type]} -- [description]
code: def test_exists(self):
      self.assertTrue(tf.io.gfile.isdir(self.path_root))
  
imports: import os
  import subprocess
  import sys
  import pytest
  import tensorflow
  import tensorflow_io
label_desc: Use image node_id 3 for calling the AZFSTestBase obj's underlying member method code with example usage: obj.test_exists() without return types